Luminescent electrical discharge device



Aug. M34. R, FOSTER ET AL 1,969,642

L-UMINESCENT ELECTRICAL DISCHARGE DEVICE Filed NOV. 22. 1933 I nventons' fiauaw Fasi'ea Patented Aug. 7, 1934 UNITED STATES PATENT OFFICE Reuben Foster and Sigmund K. Waldorf, Baltimore, Md.; Foster said Waldorf assignor to said f Application November 22, 1933, Serial No. 699,220

1 Claim.

This invention relates to new and useful improvements in electrical discharge devices. For illuminating purposes, it is desirable that devices employing electrical discharges throug gaseous 5 and vaporous atmospheres be made to yi 1d light having the desired radiation characteristics and that the light be in appreciable quantities at as low an excitation voltage as possible.

Therefore, one of the important objects of the invention is to provide a device which becomes luminous through the excitation of gases or vapors, or their combinations, at reduced pressure by the application of voltages of only a few hundred volts.

Another object of the invention is to provide an electrical discharge device wherein carbonoxygen and rare gases are used in such proportions and combinations to produce a white light.

These and various other important objects and advantages of the invention will become apparent to the reader of the following specification.

In the drawing:--

Figure 1 represents a longitudinal sectional view through the device, showing the electrodes in the gas or vapor container.

Figure 2 represents a cross sectional view taken substantially on the line 22 of Figure 1.

Referring to the drawing wherein like numerals designate like parts, it can be seen that numeral 5 denotes the light transmitting container of glass or some similar material into which the conductors 6-7 extend.

Mounted within the container 5 is the outer electrode 8 which is preferably cylindrical, but

which may be of any desired shape sufficiently expansive to encompass the inner electrode 9. Both electrodes 8 and 9 are of mesh conductor construction, the outer electrode 8 being spaced concentrically with respect to the wall of the v container 5 by the posts 10, which posts are secured to the electrode 8. The conductor 7 supports and determines the longitudinal disposition of the electrode 8, while the posts 10 support the electrode 8 definitely in a transverse plane.

The inner electrode 9, which is of mesh, is secured to the rectangular shaped frame 11, one end of the frame being provided with laterally disposed leg portions 12 which bear against the inner side of the container 5, while the conductor 6 is secured to the opposite end of the frame 11, so that the legs 12 and the conductor 6 determine the position of the frame 11 and the electrode 9 within the confines of the electrode 8 so that normally the inner electrode is slightly spaced from the outer electrode, as shown in Figure 2.

The foregoing describes the detafls of the apparatus involved and the following will describe the gaseous content for producing 'a white light.

After considerable experimentation, it has been found that when certain carbon-oxygen gases are combined with a rare gas, such as neon and helium, and used in a discharge device, such as is hereinbefore described, a bright white light is obtained. Either carbon monoxide or carbon dioxide is suitable with either neon or helium. Approximately 15% of neon or approximately 50% or 60% of helium is used in these compositions.

In preparing for the operation of this device,

the container is first evacuated to a low pressure and cleansed by methods commonly known in the technique of manufacturing gaseous and vaporous discharge tubes. After the cleansing operation has been completed, the gas or vapor,

or combination, desired permanently in the device is admitted to the container 5 at reduced pressure. The pressure preferred will vary with the nature of the atmosphere to be used in the device, the dimensions of the device, and its electrical conditions of operation, such as the current, voltage and type of power supply.

When in operation, most of the luminosity occurs in the region adjacent to the cathode. For this reason, the larger or outside electrode of the device illustrated in the drawing would be connected to the negative line when operating on continuous voltages. For alternating current operation, it is desirable that the construction of the device he modified slightly to have electrodes of more nearly equal surfaces.

Discharges in the elemental gases, such as helium and neon, can be obtained at pressures as great as 15 or 20 millimeters of mercury, while some compound gases, such as acetylene and carbon monoxide, do not permit of a discharge in the device at pressures exceeding 4 millimeters. However, the most desirable pressures for the first class of gases is about 3 mm. and for the second class about 1 /2 mm.

One of the constituents of the combinations that have been made to give white light are either carbon monoxide or carbon dioxide, which are interchangeable in the combination without noticeable difference. One of these gases combined with either approximately 15% of neon or approximately 50% or 60% of helium gives light having a very good white quality.

While the foregoing specification sets forth the invention in specific terms. it is to be understood that numerous changes in the shape, size and a. composition content of carbon-oxygen gas and A luminescent electrical discharge tube having ate a s ma be r ted t w ut departins helium in the ratio oi approximately 1 to 1.

from the spirit and scope of the invention as 5 claimed hereinafter.

Having described the invention, what is claimed as new is:-

REUBEN FOSTER.

SIGMUND K. WALDORF. 

